Running minified in Grunt cannot read property of undefined - gruntjs

Question

I'm trying to build a Grunt task that minifys my JS files and return a single minified JS file.
This is my gruntfile.js file:
module.exports = function (grunt) {
// Project configuration.
grunt.initConfig({
minified: {
files: {
src: [
'js/*.js',
],
dest: 'js/min/'
},
options: {
allinone: true
}
},
});
grunt.loadNpmTasks('grunt-minified');
};
When I run the task it does work, but it also returns an error.
> cmd.exe /c grunt -b "C:\Users\alucardu\documents\visual studio 2015\Projects\JS-demo\JS-demo" --gruntfile "C:\Users\alucardu\documents\visual studio 2015\Projects\JS-demo\JS-demo\Gruntfile.js" minified
Running "minified:files" (minified) task
Warning: Cannot read property 'yellow' of undefined Use --force to continue.
Process terminated with code 3.
Aborted due to warnings.
I've done a search action in my entire solution for 'yellow' but it doesn't return any results. Also when I empty both my JS files that are being minified it still returns the error.
Does anyone know why it's returning this error?

Answer 1

By removing the
options: {
allinone: true
}
The warning no longer showed up, but it also doesn't concat the files together. So I've added another task called concat. So now my gruntfile looks like this:
module.exports = function (grunt) {
// Project configuration.
grunt.initConfig({
watch: {
scripts: {
files: ['js/*.js'],
tasks: ['concat', 'minified', 'uglify'],
},
},
concat: {
dist: {
src: ['js/*.js'],
dest: 'js/min/concat.js'
},
},
minified: {
files: {
src: ['js/min/concat.js'],
dest: 'js/min/minified.js'
},
},
uglify: {
my_target: {
files: {
'js/min/uglify.js': ['js/min/minified.jsconcat.js']
}
}
},
});
grunt.loadNpmTasks('grunt-contrib-watch');
grunt.loadNpmTasks('grunt-contrib-concat');
grunt.loadNpmTasks('grunt-minified');
grunt.loadNpmTasks('grunt-contrib-uglify');
};
And it seems to be working fine.